Support construction for large filament lamps



Dec. 2,1930.

SUPPORT A. c. MAssIE 1,783,623

CONSTRUCTION FOR LARGE FILAUENT LAMPS Filed March 27, 1929 I? I? J AT??? N Patented Dec. 2, 1930 UNITED STATES PATENT OFFICE i ARNOLD CRAWFORD MASSIE, OF BLOOMFIELD, NEW JERSEY, ASSIGNOR TO WESTING- HOUSE LAMP COMPANY, A CORPORATION OF PENNSYLVANIA SUPPORT CONSTRUCTION FOR LARGE FILAMENT LAMPS Application filed March 27, 1929. Serial No. 350,320.

This invention relates to incandescent electric lamps and to incandescent electric lamps of the projection type, and more particularly relates to a method of mounting the concentrated light source of said projection type lamps.

In incandescent electric lamps of the projection type particularly those employing a high wattage input,itis customary to employ a concentrated light source such asasegmented coil type tungsten filament. It is essential that this filament be mounted in such manner as to be free to move vertically upon expansion and contraction during operation thereof, but restrained with respect to lateral displacement by mechanical shock or vibration incident to manufacture, shipping, handling, use and the like.

It is also essential that in the mounting of segmented coil type filament no undue mechanical stressesorstrains be applied to the filaments which would cause lateral displacements of the same upon incandescence.

One of the objects of this invention is to provide a method of mounting a segmented coil type filament in a substantially strain free position.

Another object of this invention is to im' prove the methods of mounting segmented coil type filaments.

Another object of this invention is to provide bridge support members having ad ustable suspending means from which the seg mented coil type filaments may be suspended in a substantial strain free position, free to move vertically but restrained from lateral displacement.

Another object of this invention is to provide a bridge support suspending member which is adapted to maintain the lead support wires in a substantially rigid spaced relationship.

Another object of this invention is to provide a bridge support member for use in mounting segmented coil type filaments which will ofier substantially'no resistance to the upward flow of heated inert gases from the incandesced filament.

Another object of this invention is to facilitate the manufacture and to increase the life and efliciency of incandescent electric lamps of the projection type.

Other objects and advantages will become apparent as the invention is more fully disclosed.

- In copending applications Serial No. 350,511, filed March 28, 1929, and Serial No. 350,319, filed March 27, 1929, I have disclosed respectively a method of making flexible metal to glass seals, and a mount for incandescent electric lamps. These applications are assigned to the same assignee as the present invention. In the latter identified application I have disclosed a method of mounting the filament structure of an incandescent lamp of the projection type which comprises forming a rigid filament structure comprised of lead support wires, bridge suspending members and a coil type incandescent lamp filament suspended therebetween, and mounting said rigid filament structure integral with the stem of the device by means of frictionally engaging a tubular projection member of said stem with metal collars integral with the lead wires of said rigid filament structure.

The present invention relates to the bridge support member utilized in forming the rigid filament structure and to the adjustable suspending means thereon, for mounting the segmented coil type filament from said brid e support member, and to the method 0% filament mounting described in said copending application above identified, and as will be more fully described.

- Before further disclosing the nature of the present invention reference should be had to the accompanying drawing wherein is shown Fig. 1, a side elevational View partly in cross section of an incandescent electric lamp of the projection type showing one application of the present invention wherein a concentrated light source 1, is suspended between bridge support members 2 and 3, rigidly positioning in spaced relation the refractory metal lead wires 4 and 5 integral withmetal collars 6 and 7 frictionally engaging tubular projection member 8 of the stem 9.

Fig. 2 is an enlarged side elevational view of the lower bridge support member 3, showing in more detail the method of mounting the member so as to maintain the lead support wires t and 5 in definite spaced relationship and further discloses in larger detail the adjustable suspending means comprising spacer members 10 located on said bridge suport member 3, which are utilized for mounting the coil segments in strain free position.

The bridge support suspending member 3 is preferably comprised of a metal or alloy material such as molybdenum, nickel, Monel and the like and may be of wire, rod or strap shape, as desired. For the purpose of the present invention where it is desired to utilize a bridge member having great rigidity and hot strength and a substantially low surface area exposed to and opposing the upward diffusion of heated inert gases rising from an incandesced light source, I prefer to employ a highly refractory metal such as molybdenum, in sheet or strap form, having a thickness in the neighborhood of 10 to 20 mil (.010 to .02 inches). The strap member may be of any convenient width which gives sufficient strength to rigidly support the segmented coil type filament. Such a shaped strap-like metal body is admirably adaptedto the purposes of my invention as it combines flexibility, strength and permits ready mounting means ;for the adjustable spacer members 10, as will be more fully described.

The metal bridge member is bent at each end into loops, one loop of a diameter sulficient to permit free slipping along the filament lead sup ort wire 5, and the other loop of suiiicient iameter to engage the spool portion of refractory insulating member 13, having an orifice 14 of a diameter sufficient to permit free slippage along the other filament lead support wire 4. The interposed refractory member 13 prevents electrical leakage across the filament support wires and the metal bridge and may be comprised of any good non-conducting material such as lava rock, magnesium silicate, refractory oxides and the like materials.

In this manner the metal bridge member is mounted with the edge thereof exposed to the upward diffusion of gases from the incandesced filament, when the lamp is operated in a substantial vertical position, asis normally the case.

The interposed refractory insulator 13 is further illustrated in Fig. 7, a perspective view showing the spool shape of the insulator 13 having a central opening 14 of the proper diameter to closely fit the lead wireA. A side elevational View of the same insulator 13 is shown in Fig. 8.

It will be noted that the diameter of the lead su port wires 4 and 5 above and below This is due to the fact that in forming the filament lead support wires 1 and 5, it is customary to comprise the same of a lower lesser refractory and more ductile metal such as nickel, chrome alloy, and the like and an upper highly refractory metal such as tungsten, molybdenum and the like. This is for the purpose of facilitating the mounting and assembly of the rigid filament structure as shown in Fig. 1 and as disclosed in copending application Serial No. 350,319 above identified.

These two sections are then butt-welded together, and being of different diameters form a shoulder upon which the lower bridge support member is caused to rest. To provide against Vertical displacement of the bridge member it essential that some mechanical locking means be provided whereby the tubulated end of the bridge support member 3 on lead support wire I) is substantially restrained from vertical displacen'ient. Such a locking means 15 is indicated in Fig. 1 which comprises a tight litting lock collar comprised of a spirally wound pig-tail of wire such as nickel which is slipped over the lead support wire 5 and brought snug against the bridge support member 3 and which may be are welded in position if desired. If the spiral frictionally engages the surface of the lead support wire sulliciently, arc welding thereto need not be necessary.

The upper bridge support member is similarly mounted by first forming a shoulder on the refractory metal lead support wires by grinding away the surface thereof and mounting the bridge member thereon with one end insulated from the lead wires in an analogous manner to that described in the lower bridge member.

The adjustable spacer members comprising the refractory insulator 13 and the spacer member 10 are assembled and approximately positioned on the metal bridge supporting members 2 and 3, with the tabs 12 bent over in position to frictionally engage the metal bridge support members 2 and 3. Filament extension members (16) comprised of molybdenum or the like refractory metal wires of a diameter such as to freely more in the orifice 14 of the insulator 13 and which are provided with a hooked or looped port-ion adapted to loosely engage the loop portions of the segmented coil type filament.

The spacer member 10 is adjusted along the horizontal axis of the bridge so that the filament extension member 16 is vertically above the loop portion of the filament and the tab portions of the spacer member caused to frictionally engage the bridge member so as to rigidly maintain this position. The filament extension member 16 is then drawn through the opening 14 in the refractory insulator 13 until the loop portion thereof engages the loop portion of the filament and is then positioned to a snug vertical fit by a locking means comprising a resilient stop collar, such as a helical spring or wire pig tail 17 which may be slipped over the filament extension member and drawn up snug to the refractory insulator allowing not in excess of a tenth of a mil clearance where the lower end of the spring is are welded to the filament extension member. The protruding excess of the extension member may be removed in any suitable manner, such as clipping.

This locking means substantially leaves the filament in position to freely move vertically when expanding or contracting during operation thereof as the filament extension members 16 are free to move within the insulating member 13, when the filament expands and upon contraction thereof the resilient stop collar 17 tends to restrain the filament from returning to any other vertical position than that originally imparted.

The adjustable suspending means for mounting the segmented coil type filament 1 between the metal bridge support members 2 and 3 are shown in greater detail in Fig. 2 and enlarged detail in Figs. 4, 5 and 6. In

Fig. 2 are shown the spacer members in position on the bridge support member 3. In Fig. 1 is shown a side elevational View of 30 the spacer member 10, ready for mounting on the bridge support member 3 and may be comprised of a metal clip member shaped from metal 'sheetmaterials by any convenient forming means such as by stamping, molding and the like, having a recessed portion 11 adapted to receive the spool portion of a refractory insulating material of similar design shown in perspective in Fig. 7 and ii side elevational view in Fig. 8.

Extended tab port-ions 12 are provided on said clip member which are adapted to be bent over to frictionally engage the sides of the metal strap bridge member 3, in the manner indicated in Fig. 6. The general shape of the clip member 10 and recessed portion 11 may be discerned in Fig. 5 showing a plane view of the clip member with the tab portionsunbent.

Fig. 6 shows an enlarged side elevational view of the completely assembled adjustable suspending means, wherein the refractory spool shaped insulator 1.3 is positioned in the recessed portion 11 of the spacer member 10 which is mounted on the metal bridge support member 3 and the tab portions 12 of the spacer member 10 are bent over in position to frictionally engage the fiat sides of the bridge member 3. The filament extension 7 member 16 adapted to serve as a support for 'the filament and as a guide during expansion and contraction when the filament is incandesced is shown in position passing through the orifice 14 in the insulator 13. In mounting a filament in accordance wit the present invention the filament lead support wires are first brought into fixed spaced relationship by means of the metal bridge support members 2 and 3 in the manner above noted and so that they are electrically insulated from each other by means of an interposed refractory insulating member 13.

The segmented coil type filament is then mounted in position in the manner indicated in Fig. 1, with the terminals 18 wrapped snugly about the lead support wires 1 and 5 and are welded thereto. Thereafter the filament extension members are positioned horizontally and vertically in the adjustable spacer members of the bridge member in the manner above noted. The rigid filament structure thus produced is ready for mounting on a stem in the manner described and claimed in copending application Serial No. 350,511, above identified.

The restraining effect of the points of suspension in this type of filament mountln g prevent displacement of the concentrated light source under the influence of re-crystallization effects, or to shocks incident to manufacture, handling, shipping, operation and the like. 1

Moreover such a filament structure being in strain free suspension offers less distortion due to mounting strains, than heretofore encountered. I

As above noted another advantage of the use of this metal bridge supporting member is in the diffusion of the heated gases arising from the incandescent filaments. Such heated gases contain vaporized material from the incandescent filament.

In utillzing incandescent electric lamps of the projection type it is customary to fixedly position the lamp in a parabolic reflector housing, and the projected beam of light is caused thereby to pass through the glass envelope of the device before reaching the lens of the device. Any'appreciable reduction in the light transmitting ability of the enclosing glass envelope falling within or intercepted by this projected beam of light'eiiectively reduces the luminous efficiency of the device.

The vaporized material from the heated filament is highly effective in reducing the light transmitting properties of the glass envelope by depositing thereon in a black amorphous layer and in copending application Serial No. 350,321, filed March 27, 1929, I have disclosed a method of effectually preventing the loss in luminous efiiciency of incandescent electric lamps particularly of the progection type by the provisions of ameans of reely circulating the heated gas convection currents carrying the vaporized material from the filament, and effecting a circulationof said heated gases over an area of the enclosing glass bulb maintained at temperatures below 180 C. before said gases are allowed to pass over the glass area which it is desired to maintain substantially clear and light transmitting Which glass area is maintained at temperatures substantially above 180 C.

By this method the vaporized material of the filament is caused to deposit out on the relatively cool portion of the bulb before reaching the hotter light transmitting portions which it is desired to maintain clear.

In such a method free circulation of the upwardly rising gases are essential and the herein described metal bridge support member comprised of a refractory metal strip or strap having a relatively thin edge portion resisting or exposed to the upward moving gas stream is substantially highly useful for the purposes of that invention, and provides practically free circulation of gases Within the device, accordin to the invention disclosed in the copen ing application Serial No. 350,321.

There are many other advantages and uses of the present invention which may become apparent from the specific embodiment herein described and many departures and improvements may be made in the specific construction and shape of the metal bridge member described herein and in the adjustable filament suspending means disclosed herein without essentially departing from the nature of the invention as set forth in the following claims.

What is claimed is:

1. A lamp filament retaining bridge member comprising a metal strip portion. having a plurality of horizontally adjustable spacer members, guide. members integral with said spacer members adapted to receive filament a lower bridge member arranged to rigidly maintain the filament lead Wires in spaced relationship, a plurality of horizontally adjustable spacer members on said bridge members, a segmented coil type filament positioned intermediate said bridge members and electrically connected to said filament lead wires, filament extension members engaging said adjustable spacer members, through guide members engaging said spacer members, and resilientdock collar means on said filament extension members for vertically suspending said filament and preventing vertical displacement of said filament on contraction after incandescing.

6. An incandescent electric lamp comprising a bulb, a filament, bridge members supporting said filament, filament extension members engaging said bridge members, through horizontally adjustable spacer members on said bridge members, and lock collar means for vertically supporting said filament extension members in said spacer member.

7. ,An incandescent electric lamp comprising a bulb, a filament, bridge support members integral with the filament, lead wires supporting said filament, horizontally adjustable spacer members on said bridge support members adapted to receive filament extension members and lock collar neans for vertically positioning said filament extension members on said horizontally adjustable spacer members.

In testimony whereof, I have hereunto subscribed my name this 22 day of March, 1929. 1

ARNOLD CRAlVFORD MASSIE.

extension members and means on said filament extension members for member vertically.

2. A lamp filament retaining bridge mem ber comprising a metal strip portion having a plurality of horizontally ad ustable spacer members, arranged to receive filament extension members and lock collar means for positioning the filament extension members vertically in said spaced members.

3. A lamp filament retaining bridge member comprising a metal strip portion, a plurality of horizontally adjustable spacer mem-- bers thereon, filament extension members engagingsaid spacer members and means comprising resilient sto collars on said filament extension members ibr vertically positioning the filament.

4. A lamp filament retaining bridge member comprising a metal strip portion, a plurality of horizontally adjustable spacer members thereon, filament extension members engaging said spacer members and means comprising resilient cushion stop. collars on said filament extension members for vertically popositioning the sitioning the lamp filament.

5. A lamp filament mount comprising filament lead Wires, an upper bridge member and 

